Portion of a boot



FIG. 1 is a front perspective view of a portion of a boot, showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a front view thereof; and,

FIG. 5 is a top view thereof.

The broken line showing of the heel, sole, portions of the boot is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a boot, as shown and described. 